Drill guide

ABSTRACT

Drill guide bushing supported on legs with inner surfaces defining angle bisected by longitudinal axis of bushing and with flat coplanar bottoms in plane perpendicular to longitudinal axis of bushing. Scribe line on apparatus bisecting sand angle permits visual alignment of bushing with one of two mutually perpendicular center lines on surface to be drilled. Selected edges of legs lie in same plane as longitudinal axis of bushing and permit visual alignment of bushing with other center line. When drilling in flat surface, flat bottoms of legs contact surface. When drilling in curved surface, inner surfaces of legs tangentially contact surface.

United States Patent Leff et al.

[451 May 9, 1972 [54] DRILL GUIDE [72] Inventors: Millard Left, Whitehouse Station; Joseph Daniel Malazinsky, Middlesex; Earl Howard .Welgel, Bridgewater, all of NJ.

[73] Assignee: Ajem Associates, Inc., Somerville, NJ.

[22] Filed: June 15, 1970 [21] Appl. No.1 46,301

FOREIGN PATENTS OR APPLICATIONS 661,420 1 1/1951 Great Britain ..408/72 Primary Etaminer-Gil Weidenfeld Attorney-Jack Schuman 1 ABSTRACT Drill guide bushing supported on legs with inner surfaces defining angle bisected by longitudinal axis of bushing and with flat coplanar bottoms in plane perpendicular to longitudinal axis of bushing. Scribe line on apparatus bisecting sand angle permits visual alignment of bushing with one of two mutually perpendicular center lines on surface to be drilled. Selected edges of legs lie in same plane as longitudinal axis of bushing and permit visual alignment of bushing with other center line. When drilling in flat surface, flat bottoms of legs contact surface. When drilling in curved surface, inner surfaces of legs tangentially contact surface.

5 Claims, 5 Drawing Figures 3,328,890 7/1967 Fagerberg, Sr. ..33/1 89 3,381,551 5/1968 Lavering et al ..408/72 BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to apparatus for guiding a drill. More specifically, this invention relates to apparatus for maintaining a rotating drill perpendicular to a flat or curved surface.

2. Description of the Prior Art In using manually held drills, particularly the well-known hobbyists or home handyman's inch or V4 inch electric drill, it often is necessary to drill perpendicularly to a flat surface or to a curved surface such as a shaft having a circular cross section. Experience has shown that it is quitedif'ficult, if not impossible, to start the drill at the desired point perpendicular to the surface being drilled, and even more difficult, if not impossible, to maintain such drill in perpendicular position during the course of the drilling operation. While this is certainly true in respect to horizontal surfaces, it is even truer for vertical surfaces, particularly those in barely accessable areas.

Efforts have been made in the past to provide a suitable drill guide to solve the foregoing problem, as exemplified by the following U.S. Pat. Nos.:

2,501,036 1959) to Fay 2,635,348 (1953) to Jones 2,936,657 (1960) to Berlin et al.

3,064,504 (1962) to .larboe 3,282,132 (1966) to Neuschotz None of the foregoing patents provided a simple, rugged, easily used tool permitting drills of various sizes to be quickly visually centered over the intersection of two mutually perpendicular center lines, the said tool starting and maintaining the rotating drill in perpendicular position whether drilling on a flat surface or on a curved surface.

SUMMARY OF THE INVENTION One of the objects of this invention is to provide an improved guide for drills.

Another of the objects of this invention is to provide improved apparatus for maintaining a rotating drill perpendicular to a flat or to a curved surface.

Yet another of the objects of this invention is to provide a simple, rugged, inexpensive, easily used tool permitting drills of various sizes to be quickly visually centered over the intersection of two mutually perpendicular center lines, the said tool starting and maintaining the rotating drill in perpendicular position whether drilling on a flat surface or on a curved surface.

Other and further objects of this invention will become apparent during the course of the following description and by reference to the accompanying drawing and the appended claims.

Briefly, we have discovered that the foregoing objects may be attained by removably mounting a drill-receiving bushing at the vertex of two legs, the longitudinal axes of the bushing bisecting the angle defined by the inner surfaces of the two legs, a scribe line on the apparatus along the bisector of the said angle permitting the apparatus to be visually aligned with one center line marked on the article to be drilled, edges of the two legs and the longitudinal axis of the bushing lying in a plane perpendicular to the plane defined by the said scribe line and the longitudinal axis of the bushing, the said edges being adapted to be visually aligned with another center line marked on the article to be drilled and perpendicular to the first mentioned center line. The bottoms of the legs are flattened and lie in a plane perpendicular to the longitudinal axis of the bushing and adapted to contact a flat surface. The insides of the legs preferably are straight and are adapted to tangentially contact a curved surface.

BRIEF DESCRIPTION OF THE DRAWING Referring now to the drawing, in which like numerals represent like parts in the several views:

FIG. I represents a view in side elevation of the apparatus of the present invention, a drill and the longitudinal axis of the bushing being shown in phantom.

FIG. 2 represents a view in plan of the apparatus of the present invention, the phantom lines representing portions of two mutually perpendicular intersecting center lines marked on the surface of an article to indicate the center of a hole to be drilled.

FIG. 3 represents a view in end elevation of the apparatus of the present invention, the drill being shown in phantom as well as a fiat surface into which a perpendicular hole is to be drilled.

FIG. 4 represents a view in end elevation of the apparatus of the present invention, similar to FIG. 3, the phantom line indicating a curved surface into which a perpendicular hole is to be drilled. 1

FIG. 5 represents a detail showing the bushing in medial section and the adjacent supporting structure in section, the drill being shown in phantom.

DESCRIPTION OF THE PREFERRED EMBODIMENT The apparatus of the present invention is seen as comprising an elongated member 1 having legs 2 and 3 at one end thereof and legs 4 and 5 at the other end thereof. A vertical recess 6 extends entirely through elongated member 1 adjacent legs 2 and 3, the said recess 6 receiving a bushing 7, the said bushing 7 preferably being secured in recess 6 by suitable means such as a screw 8.

Legs 2', and 3 have flat inner surfaces 9 and 10, respectively, defining therebetween an angle which is bisected by the longitudinal axis 11 of bushing 7, as shown in FIGS. 3 and 4. Bushing 7 is adapted to snugly rotatably and therefore slidably receive a drill l2 and it will, therefore, be apparent that the longitudinal axis of drill 12 registers with the longitudinal axis 11 of bushing 7. Drill 12 is rotated by suitable means (not shown) such as the conventional /4 inch electric drill. It will be apparent that the length of drill 12 should be sufficient to permit drill 12 to be extended through the apparatus and into the article being drilled to the depth of the hole desired.

At the intersection of legs 2 and 3, a line 13 bisecting the angle between inner surfaces 9 and 10, respectively, of the said legs 2 and 3 is scribed into the article for a purpose to be described hereinafter. It will be apparent that line 13 is parallel to the longitudinal axis 1 l of bushing 7.

Legs 2 and 3 have flat bottoms I4 and 15, respectively, which lie in a plane perpendicular to'the longitudinal axis 11 of bushing 7.

Legs 4 and 5 have the same aspect in end elevation as legs 2 and 3, respectively. In other words, legs 4 and 5 have flat inner surfaces which register, in end elevation, with surfaces 9 and 10 of legs 2 and 3, respectively, and therefore define the same angle as that defined by surfaces 9 and 10. Moreover, legs 4 and 5 have flat bottoms 16 which lie in the same plane as flat bottoms 14 and 15 of legs 2 and 3, respectively.

Legs 2 and 3 preferably are offset or staggered with respect to each other relative to one end of elongated member I so that the rear edge 17 of leg 2, the forward edge 18 of leg 3, and the longitudinal axis 11 of bushing 7 lie in the same plane, for reasons hereinafter appearing, as shown particularly in FIG. 2.

The plane defined by rear edge 17 of leg 2, the forward edge 18 of leg 3, and the longitudinal axis 11 of bushing 7, is perpendicular to the plane defined by line 13 and the longitudinal axis 1 1 of bushing 7.

Bushing 7 is sized to receive a drill 12 having a particular diameter. It will be apparent that, to enable the apparatus of the present invention to be employed in guiding drills of various sizes, several bushings 7 may be required, each specific to one particular drill size and each adapted to be seated in recess 6 and secured therein by screw 8.

The operation of the invention will now be described.

It will be understood that, on whatever the nature of the surface into which a perpendicular hole is to be drilled i.e., flat or curved), two mutually perpendicular lines 19 and 20 may advantageously be drawn, as shown in phantom in FIG. 2, the

' intersection of the said lines 19 and 20 establishing the center of the hole to be drilled.

When the surface into which the hole is to be drilled is fiat surface 21, as shown in FIG. 3, the apparatus is positioned so that flat bottoms 14, 15 and 16 of legs 2, 3, 4 and 5 contact the said fiat surface 21. Scribed line 13 on the apparatus is visually aligned with center line 19, thereby aligning or indexing the longitudinal axis 11 of bushing 7, and hence the longitudinal axis of the drill 12 subsequently to be inserted in and guided by the said bushing 7, with center line 19. Rear edge 17 'of leg 2 and forward edge 18 of leg 3 are visually aligned with center line 20, thereby aligning or indexing the longitudinal axis 11 of bushing 7, and hence the longitudinal axis of drill 12 subsequently to be inserted in and guided by the said bushing 7, with center line 20. The longitudinal axis 11 of bushing 7 will now lie over the center of the desired hole perpendicular to flat surface 21. The apparatus is now firmly held in position, as by suitably clamping or manually holding elongated member 1, and drill 12 is inserted into bushing 7 and rotated to drill the desired perpendicular hole in fiat surface 21.

When the surface into which the hole is to be drilled is a curved surface, such as the circular shaft 22 shown in FIG. 4, the apparatus is positioned so that the inner surfaces 9 and 10 of legs 2 and 3, and the corresponding inner surfaces of legs 4 and 5, tangentially contact said curved surface 22. Upon visually aligning scribed line 13 with center line 19, and the rear and forward edges 17 and 18 of legs 2 and 3, respectively, with center line 18, the longitudinal axis 11 of bushing 7 will lie over the center of the desired hole perpendicularly to the curved surface 22 Upon securing the apparatus as hereinbefore described, drill 12 may be inserted in bushing 7 and rotated to drill thedesired hole.

The staggered or offset arrangement of legs 2 and 3, whereby the rear edge 17 of leg 2 and the forward edge 18 of leg 3 are employed in the visual alignment process, permits a more accurate alignment under certain conditions. Under other conditions, legs 2 and 3 may be aligned with each other rather than being relatively staggered or offset, in which event the said legs 2 and 3 may be disposed with respect to bushing 7 so that the rear (or the forward) edges of legs 2 and 3 and the longitudinal axis 11 of bushing 7 lie in the same plane. in the operation of this modification of the apparatus, the rear (or the forward) edges of legs 2 and 3 would then be visually aligned with center line 20 and the operation continued as hereinbefore described.

We claim:

1. Apparatus for guiding a rotatable drill perpendicular to a fiat or selectively to a curved surface thereby to drill a perpendicular hole in said surface at a location fixed by the intersection of two mutually perpendicular center lines marked on the said surface, said apparatus comprising:

a. an elongated member having a recess extending therethrough,

b. a guide bushing removably secured in said recess, said guide bushing having an aperture extending therethrough and adapted to receive and guide a rotatable drill,

c. a first pair of legs secured to said elongated member adjacent said guide bushing, the said legs having facing inner surfaces defining an angle bisected by the longitudinal axis of the aperture in said guide bushing,

d. a second pair of legs secured to said elongated member andspaced from said first pair of legs, the legs of said second pair having facing inner surfaces registering with the facing inner surfaces of the legs of said first pair and thereby defining the same angle as the angle defined by the facing inner surfaces of the legs of said first pair,

e. the bottoms of all of said legs lying in a common plane perpendicular to the longitudinal axis of the aperture of the guide bushing,

f. a scribed line on said apparatus at the intersection of said first pair of le said. scribed line bisectin defined by the acing inner surfaces of saidfi legs and adapted to index the apparatus over center lines,

g. an edge of one of said first pair of legs, an edge of the other of said first pair of legs, and the longitudinal axis of the aperture of the guide bushing all lying in the same plane which plane is perpendicular to the plane defined by the scribed line and the longitudinal axis of the aperture of the guide bushing, said edges being adapted to be aligned to index the apparatus over .the other of said center lines,

h. the bottoms of all of said legs being adapted to contact a flat surface when the rotatable drill is to drill a hole in said flat surface,

i. the facing inner surfaces of all of said legs being'adapted to tangentially contact a curved surface when the rotatable drill is to drill a hole perpendicularly in said curved surface.

2. Apparatus as in claim 1, wherein:

j. the legs of said first pair of legs are staggered relative to each other, the forward edge of one leg relative to one end of the apparatus and the rear edge of the other leg relative to said one end of the apparatus and the longitudinal axis of the aperture of the guide bushing all lying inthe same plane.

3. Apparatus for guiding a rotatable drill perpendicular to a flat or selectively to a curved surface, said apparatus comprismg:

a. sleeve means having a longitudinal axis and adapted to receive and guide a rotatable drill,

b. leg means secured to said sleeve means, said leg means having facing inner surfaces defining an angle bisectedby the longitudinal axis of said sleeve means, the bottoms of said leg means lying in a common plane perpendicular to the longitudinal axis of said sleeve means,

c. the bottoms of said leg means being adapted to contact a flat surface when the rotatable drill is to drill a hole perpendicularly in said fiat surface,

. the facing inner surfaces of said leg means being adapted to tangentially contact a curved surface when the rotatable drill is to drill a hole perpendicularly in said curved surface,

the angle rlt pair of one of said e. said leg means comprises a pair of legs adjacent said I pair of legs, said scribed line bisecting the angle defined by the inner surfaces of said pair of legs and adapted to index the apparatus in a first direction over a specific lo-' cation on the surface to be drilled,

g. an edge of one of said pair of legs, an edge of the other of said pair of legs, and the longitudinal axis of said sleeve means all lying in the same plane which plane is perpendicular to the plane defined by said scribed line and the longitudinal axis of said sleeve means, said edges being adapted to be aligned to index the apparatus in a second direction perpendicular to said first location over the specific location on the surface to be drilled.

. Apparatus as in claim 3, wherein:

h. the legs of said pair of legs are staggered relative to each other, the forward edge of one leg relative to one end of the apparatus and the rear edge of the other leg relative to said one end of the apparatus and the longitudinal axis of the sleeve means all lying in the same plane.

5. Apparatus as in claim 3, wherein:

h, said leg means further comprises a second pair of legs spaced from said first mentioned pair of legs,

i. an elongated member secured at one end to said first mentioned pair of legs and secured at the other end to said second pair of legs, said elongated member being adapted to be grasped to secure the apparatus over a specific location on the surface to be drilled. 

1. Apparatus for guiding a rotatable drill perpendicular to a flat or selectively to a curved surface thereby to drill a perpendicular hole in said surface at a location fixed by the intersection of two mutually perpendicular center lines marked on the said surface, said apparatus comprising: a. an elongated member having a recess extending therethrough, b. a guide bushing removably secured in said recess, said guide bushing having an aperture extending therethrough and adapted to receive and guide a rotatable drill, c. a first pair of legs secured to said elongated member adjacent said guide bushing, the said legs having facing inner surfaces defining an angle bisected by the longitudinal axis of the aperture in said guide bushing, d. a second pair of legs secured to said elongated member and spaced from said first pair of legs, the legs of said second pair having facing inner surfaces registering with the facing inner surfaces of the legs of said first pair and thereby defining the same angle as the angle defined by the facing inner surfaces of the legs of said first pair, e. the bottoms of all of said legs lying in a common plane perpendicular to the longitudinal axis of the aperture of the guide bushing, f. a scribed line on said apparatus at the intersection of said first pair of legs, said scribed line bisecting the angle defined by the facing inner surfaces of said first pair of legs and adapted to index the apparatus over one of said center lines, g. an edge of one of said first pair of legs, an edge of the other of said first pair of legs, and the longitudinal axis of the aperture of the guide bushing all lying in the same plane which plane is perpendicular to the plane defined by the scribed line and the longitudinal axis of the aperture of the guide bushing, said edges being adapted to be aligned to index the apparatus over the other of said center lines, h. the bottoms of all of said legs being adapted to contact a flat surface when the rotatable drill is to drill a hole in said flat surface, i. the facing inner surfaces of all of said legs being adapted to tangentially contact a curved surface when the rotatable drill is to drill a hole perpendicularly in said curved surface.
 2. Apparatus as in claim 1, wherein: j. the legs of said first pair of legs are staggered relative to each other, the forward edge of one leg relative to one end of the apparatus and the rear edge of the other leg relative to said one end of the apparatus and the longitudinal axis of the aperture of the guide bushing all lying in the same plane.
 3. Apparatus for guiding a rotatable drill perpendicular to a flat or selectively to a curved surface, said apparatus comprising: a. sleeve means having a longitudinal axis and adapted to receive and guide a rotatable drill, b. leg means secured to said sleeve means, said leg means having facing inner surfaces defining an angle bisected by the longitudinal axis of said sleeve means, the bottoms of said leg means lying in a common plane perpendicular to the longitudinal axis of said sleeve means, c. the bottoms of said leg means being adapted to contact a flat surface when the rotatable drill is to drill a hole perpendicularly in said flat surface, d. the facing inner surfaces of said leg means being adapted to tangentially contact a curved surface when the rotatable drill is to drill a hole perpendicularly in said curved surface, e. said leg means comprises a pair of legs adjacent said sleeve means, f. a scribed line on said apparatus at the intersection of said pair of legs, said scribed line bisecting the angle defined by the inner surfaces of said pair of legs and adapted to index the apparatus in a first direction over a specific location on the surface to be drilled, g. an edge of one of said pair of legs, an edge of the other of said pair of legs, and the longitudinal axis of said sleeve means all lying in the same plane which plane is perpendicular to the plane defined by said scribed line and the longitudinal axis of Said sleeve means, said edges being adapted to be aligned to index the apparatus in a second direction perpendicular to said first location over the specific location on the surface to be drilled.
 4. Apparatus as in claim 3, wherein: h. the legs of said pair of legs are staggered relative to each other, the forward edge of one leg relative to one end of the apparatus and the rear edge of the other leg relative to said one end of the apparatus and the longitudinal axis of the sleeve means all lying in the same plane.
 5. Apparatus as in claim 3, wherein: h. said leg means further comprises a second pair of legs spaced from said first mentioned pair of legs, i. an elongated member secured at one end to said first mentioned pair of legs and secured at the other end to said second pair of legs, said elongated member being adapted to be grasped to secure the apparatus over a specific location on the surface to be drilled. 